CRVO Quiz: 10 Questions with Explanations:
Where does CRVO most commonly occur?
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A) Optic disc
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B) Macula
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C) Fovea
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D) Periphery
✅ A) Optic disc — CRVO occurs at the level of the optic disc, where the central retinal vein exits the eye alongside the central retinal artery, making it vulnerable to compression and thrombosis.
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What is the classic fundus sign of CRVO?
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A) Hard exudates
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B) Flame hemorrhages
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C) Cotton wool spots
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D) Drusen
✅ B) Flame hemorrhages — CRVO causes diffuse flame-shaped hemorrhages in all four retinal quadrants, a hallmark finding due to venous backpressure.
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CRVO is associated with which condition?
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A) Hypotension
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B) Low cholesterol
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C) Hypertension
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D) Hypothyroidism
✅ C) Hypertension — High blood pressure is the most common systemic association with CRVO, causing arterial stiffening that compresses the adjacent central retinal vein.
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Which complication is most feared in CRVO?
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A) Cataract
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B) Neovascular glaucoma
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C) Retinal detachment
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D) Optic atrophy
✅ B) Neovascular glaucoma — Ischemic CRVO triggers VEGF release, driving new vessel growth on the iris (rubeosis iridis) that can block the drainage angle and cause painful, sight-threatening glaucoma.
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Which test distinguishes ischemic from non-ischemic CRVO?
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A) OCT
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B) Visual field
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C) FFA (fluorescein angiography)
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D) Color vision test
✅ C) FFA — Fluorescein angiography reveals the extent of capillary non-perfusion, which is the key feature that separates ischemic (>10 disc areas) from non-ischemic CRVO.
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What is the first-line treatment for macular edema in CRVO?
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A) Laser photocoagulation
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B) Anti-VEGF injections
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C) Oral steroids
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D) Vitrectomy
✅ B) Anti-VEGF injections — Intravitreal anti-VEGF agents (like ranibizumab or bevacizumab) are the gold-standard treatment for macular edema secondary to CRVO, reducing fluid and improving vision.
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Which nerve fiber is affected in CRVO?
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A) Optic nerve
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B) Oculomotor nerve
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C) Retinal ganglion cells
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D) Ciliary nerve
✅ C) Retinal ganglion cells — Venous congestion and ischemia in CRVO damage retinal ganglion cells, whose axons form the optic nerve, leading to progressive visual loss.
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What is the classic symptom of CRVO?
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A) Eye pain
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B) Double vision
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C) Sudden painless vision loss
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D) Flashing lights
✅ C) Sudden painless vision loss — CRVO typically presents as sudden, painless blurring or loss of vision in one eye, caused by venous obstruction and resulting retinal ischemia.
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How many retinal quadrants show hemorrhages in CRVO?
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A) 1
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B) 2
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C) 3
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D) 4
✅ D) 4 — Unlike branch RVO which affects one quadrant, CRVO causes hemorrhages in all four retinal quadrants because the entire venous drainage of the retina is blocked.
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Which imaging best shows macular edema in CRVO?
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A) X-ray
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B) MRI
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C) OCT
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D) B-scan ultrasound
✅ C) OCT — Optical coherence tomography (OCT) is the gold standard for detecting and monitoring cystoid macular edema in CRVO, showing intraretinal fluid accumulation in cross-section.
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